Supported Chains
Networks and assets supported by OpenX402
The OpenX402 facilitator at facilitator.openx402.ai supports multiple chains for payment settlement. Networks are identified using CAIP-2 format.
You can query supported networks live at facilitator.openx402.ai/supported.
Base (Mainnet)
| Property | Value |
|---|---|
| Network ID | eip155:8453 |
| Chain ID | 8453 |
| Asset | USDC |
| Contract | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| Payment Method | EIP-3009 transferWithAuthorization |
The primary settlement chain. Most x402 transactions settle on Base.
Monad (Mainnet)
| Property | Value |
|---|---|
| Network ID | eip155:143 |
| Chain ID | 143 |
| Asset | USDC |
| Contract | 0x754704Bc059F8C67012fEd69BC8A327a5aafb603 |
| Payment Method | EIP-3009 transferWithAuthorization |
Monad is a high-performance EVM chain. Registration and settlement work identically to Base — the facilitator signs EIP-3009 authorizations on Monad's USDC contract.
Base Sepolia (Testnet)
| Property | Value |
|---|---|
| Network ID | eip155:84532 |
| Chain ID | 84532 |
| Asset | USDC |
| Contract | 0x036CbD53842c5426634e7929541eC2318f3dCF7e |
| Payment Method | EIP-3009 transferWithAuthorization |
Use Base Sepolia for development and testing. You can get testnet USDC from the Circle faucet.
Solana (Mainnet)
| Property | Value |
|---|---|
| Network ID | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Legacy Network ID | solana |
| Asset | USDC |
| Mint | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v |
| Payment Method | SPL Token TransferChecked |
| Fee Payer | 5xvht4fYDs99yprfm4UeuHSLxMBRpotfBtUCQqM3oDNG |
Solana payments use SPL Token TransferChecked instructions. The facilitator acts as the fee payer for settlement transactions, so payers don't need SOL for gas.
The canonical network identifier uses CAIP-2 format (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp). The legacy identifier solana is also accepted for backward compatibility and is automatically normalized by the facilitator.
Solana Client Example
import { wrapFetch } from "x402-fetch";
import { svm } from "x402/shared";
const signer = await svm.createSignerFromBase58(process.env.SOLANA_PRIVATE_KEY);
const x402Fetch = wrapFetch(fetch, signer);
const response = await x402Fetch("https://your-server.com/api/premium");Adding Chains
More chains can be added to the facilitator. Check the /supported endpoint for the latest list.